Supercritical fluid delivery system for semiconductor wafer processing

Abstract

An elevated pressure and temperature fluid processing system providing a pressurized fluid delivery system including a process fluid supply system and pump for supplying a process fluid at a process pressure, and a process fluid heater for heating the process fluid; a process chamber with a process chamber heater; and a process discharge collection system. The system also provides a process chamber inflow valve for connecting the pressurized fluid delivery system to the process chamber for fluid flow, and a process chamber outflow valve for connecting the process chamber to the collection system for fluid flow. A process chamber bypass valve connects the pressurized fluid delivery system to the process discharge collection system so as to bypass the process chamber. A computer control system controls the pump, the process fluid heater, the chamber heater, and the valves.

1 . An elevated pressure and temperature fluid processing system comprising: 
 a pressurized fluid delivery system including a process fluid supply system and pump for supplying a process fluid at a pressure of at least a process pressure, and a process fluid heater for heating said process fluid;    a process chamber with a process chamber heater; and    a process discharge collection system;    a process chamber inflow valve for connecting said pressurized fluid delivery system to said process chamber for fluid flow;    a process chamber outflow valve for connecting said process chamber to said collection system for fluid flow;    a process chamber bypass valve for connecting said pressurized fluid delivery system to said process discharge collection system so as to bypass said process chamber; and    a computer control system controlling said pump, said process fluid heater, said chamber heater, and said valves.    
   
   
       2 . The system according to  claim 1  wherein said pressurized fluid delivery system comprises a process fluid re-circulation system, and wherein said pump functions continuously.  
   
   
       3 . The system according to  claim 2  wherein said process fluid re-circulation system comprises: 
 a first valve whereby said process fluid supply system and pump are isolated from said first process fluid heater and said chamber when said first valve is closed;    a check valve disposed between said process fluid re-circulation system and a process fluid source;    a temperature control device whereby said process fluid is maintained in a liquid phase;    a re-circulation loop whereby said process fluid in said liquid phase is directed through said temperature control device and said pump.    
   
   
       4 . The system according to  claim 1 , said process discharge collection system further comprising a recovery volume connecting to said process chamber for receiving a rapid discharge of process reagents from said process chamber, and recovery volume control valves for selecting and de-selecting said recovery volume from said process discharge collection system, said recovery volume control valves being controlled by said computer control system.  
   
   
       5 . The system according to  claim 1 , said chamber heater comprising a heating subsystem with inflow and outflow lines connecting a source of a preheated heat transfer medium to at least one heat exchanger in said process chamber and control valves for controlling the circulation of said preheated heat transfer medium through said heat exchanger, said control valves being controlled by said computer control system for achieving a desired heating effect within said chamber.  
   
   
       6 . The system according to  claim 1 , said process fluid being carbon dioxide.  
   
   
       7 . The system according to  claim 1 , said process being a supercritical phase process for cleaning and processing devices chosen from the group of devices consisting of semiconductor wafers, masks, light emitting diodes, and disk drive components.  
   
   
       8 . The system according to  claim 1  further comprising: 
 a pressurized additives delivery system including an additives supply system and pump for supplying additives at a pressure of at least said process pressure, and an additives heater for heating said additives to a pre-process temperature suitable for mixing with said process fluid;    a directional valve and mixer disposed between said process fluids heater, said process chamber, and said additives heater;    said additives heater and said directional valve being controlled by said computer control system;    said pressurized fluid delivery system and said pressurized additives delivery system being connected to said directional valve such that a computer controlled ratio of process fluids and additives can be admitted into said mixer and heater at selected respective temperatures.    
   
   
       9 . The system according to  claim 8  further comprising: 
 a mixture heater;    said mixture heater being disposed between said mixer and said process chamber; and    said mixture heater heating said mixture to at least a process temperature.    
   
   
       10 . The system according to  claim 8  wherein said pressurized additives delivery system comprises an additives re-circulation system, and wherein said pump functions continuously.  
   
   
       11 . The system according to  claim 10  wherein said additives re-circulation system comprises: 
 a first valve whereby said additives supply system and pump are isolated from said additives heater and said mixer when said first valve is closed;    a check valve disposed between said additives re-circulation system and an additives source;    a temperature control device whereby said additives are maintained at a selected temperature;    a re-circulation loop whereby said additives are directed through said temperature control device and said pump.    
   
   
       12 . The system according to  claim 3 , said process discharge collection system further comprising at least one separator for separating phases and constituents from the process discharge.  
   
   
       13 . The system according to  claim 12 , further comprising a return line from said collection system to said pressurized fluid delivery system.  
   
   
       14 . The system according to  claim 12 , further comprising a return line from said collection system to said pressurized additives delivery system.  
   
   
       15 . The system according to  claim 8  wherein said additive heater, said process chamber heater, and said process fluid heater are each selected from the group of heaters consisting of heat exchangers and electric resistance heaters.